卵黏蛋白:结构组成、理化性质、在浓蛋白液化中的作用及营养调控

鸡蛋是最好的动物源蛋白之一,其蛋白中的卵黏蛋白(3.5%)对浓蛋白凝胶性、哈夫单位起主要作用,鸡蛋中卵黏蛋白含量及存在形式是影响鸡蛋蛋白品质的主要因素,从而影响鸡蛋的可接受性。本文简要综述了卵黏蛋白的结构组成、理化性质、在浓蛋白液化过程中的作用和可能机制以及营养调控途径,为调控鸡蛋蛋白品质提供参考。

四个蛋鸡品种(系)鸡蛋中蛋黄、浓蛋白、稀蛋白比例的研究

试验分析了海兰褐壳蛋鸡、淮南麻黄鸡、贵妃鸡和D1系4个蛋鸡品种(系)所产鸡蛋的蛋黄比例、浓蛋白比例、稀蛋白比例及浓稀比。结果表明:淮南麻黄鸡、贵妃鸡和D1系的蛋黄比例显著高于海兰蛋鸡(P<0.05),浓蛋白比例显著低于海兰蛋鸡(P<0.05);海兰蛋鸡的浓稀比最高达1.19,贵妃鸡最低仅0.91;D1系母鸡30周龄鸡蛋浓蛋白、稀蛋白及蛋黄比例与40、50周龄时显著相关(P<0.05或P<0.01)。D1系稀蛋白比例、浓稀比与蛋重均呈显著正相关(P<0.01或P<0.05),蛋黄比例与蛋重显著负相关(P<0.01),蛋黄比例、浓蛋白比例、稀蛋白比例及浓稀比均与哈氏单位无显著相关(P>0.05)。

喷射蒸煮结合超滤技术制备大豆分离蛋白及其表征

以商业功能性大豆浓缩蛋白为原料,通过喷射蒸煮结合超滤技术,制备一种高纯度、高溶解性、低异黄酮、易消化的大豆分离蛋白。主要制备过程为:商业功能性大豆浓缩蛋白调pH值至9.0,进行胶体磨处理,120℃、90 s喷射蒸煮处理,再过80 ku超滤膜,所得蛋白分散液经酸沉、复溶、透析得大豆分离蛋白。所制备的蛋白纯度为84.63%(提高17.06%),氮溶指数为76.48%(提高67.71%),异黄酮含量由0.15 mg/g降至0.07 mg/g,且更容易被消化。相比于商业大豆浓缩蛋白,所制备的蛋白品质改善,制备工艺简单,可开发应用于特定人群专用蛋白配料。

铁和锰对桑蚕丝蛋白构象转变的影响

采用电感耦合等离子体质谱和原子吸收光谱对桑蚕丝腺体和蚕茧丝中Fe和Mn的含量进行表征,同时采用拉曼光谱研究Fe(Ⅲ)和Mn(Ⅱ)对高浓度再生桑蚕丝蛋白水溶液中丝蛋白构象的影响.研究结果表明,桑蚕丝纤维中Fe的含量高于其在丝腺体中的含量,而Mn的含量则相反.在丝腺体中,Fe的含量从丝腺体的后部到前部逐渐增加;但Mn含量的变化趋势与Fe不同,它在丝腺体中部的含量最低.Fe(Ⅲ)能够诱导丝蛋白的构象由无规线团和/或螺旋结构向β-折叠转变,但是Mn(Ⅱ)对丝蛋白的构象没有明显的影响.

The effect of exogenous sugar solution and high concentration of CO_2 on the contents of sugar and protein of Betula platyphylla leaves

The content of total sugar, sucrose, fructose and protein in the leaves of3-yr.-old Betula platyphylla was measured after the treatment by three exogenous sugar solutions(sucrose, fructose, glucose) and three high concentrations of CO_2 (700, 1 400, 2 100 μL/L·L^(-1))for about a month in 1998. The results showed that spraying three exogenous sugar solutionsincreased markedly the content of sugar and protein of leaves under 700 μL·L^(-1) and 1 400μL·L^(-1) CO_2 The effect of spraying exogenous sucrose solution was the best among the threeexogenous sugars. The treatment of spraying exogenous sugar solution and 2 100 μL·L^(-1) CO_2constrained the accumulation of total sugar and protein of leaves. There was no difference inprotein content of leaves when spraying glucose and fructose solutions under 700 μL·L^(-1) and 1400 μL·L^(-1) CO_2. The treatment of 2 100 μL·L^(-1) CO_2 concentration significantly increasedthe contents of total sugar, sucrose, fructose, and protein of leaves compared with that of the 700μL·L^(-1) and 1 400 μL·L^(-1) CO_2 except the plants spraying fructose solution. There waspositive correlation between the content of sugar of leaves and CO_2 concentration when sprayingsame exogenous sugar solution.

Effects of Temperature on Determination of Protein Concentration with Coomassie Brilliant Blue Method

[Objective] This study aimed to investigate the effects of temperature on determination of protein concentration with Coomassie Brilliant Blue method,thus proving advice and guidance for accurate determination of protein concentration.[Method] With Coomassie Brilliant Blue method,the concentrations of different bovine serum albumin samples were determined under different temperatures and incubation time.[Result] According to the standard curve,when the determination range of protein concentration was 0-100 mg/ml,the determined protein concentration was relatively stable after incubation at 20 ℃ for 20-30 min.Furthermore,the determination result of higher protein concentration with Coomassie Brilliant Blue method was less affected by various factors.[Conclusion] In determination of protein concentration with Coomassie Brilliant Blue method,temperature,sample concentration and incubation time were important factors affecting the accuracy of experimental results.

Physiological levels of ATP negatively regulate proteasome function

Intracellular protein degradation by the ubiquitin-proteasome system is ATP dependent, and the optimal ATP concentration to activate proteasome function in vitro is -100 μM. IntraceUular ATP levels are generally in the low millimolar range, but ATP at a level within this range was shown to inhibit proteasome peptidase activities in vitro. Here, we report new evidence that supports a hypothesis that intracellular ATP at the physiological levels bidirectionally regulates 26S proteasome proteolytic function in the cell. First, we confirmed that ATP exerted bidirectional regulation on the 26S proteasome in vitro, with the optimal ATP concentration （between 50 and 100μM） stimulating proteasome chymotrypsin-like activities. Second, we found that manipulating intracellular ATP levels also led to bidirectional changes in the levels of proteasome-specific protein substrates in cultured cells. Finally, measures to increase intracellular ATP enhanced, while decreasing intraceHular ATP attenuated the ability of proteasome inhibition to induce cell death. These data strongly suggest that endogenous ATP within the physiological concentration range can exert a negative impact on proteasome activities, allowing the cell to rapidly upregulate proteasome activity on ATP reduction under stress conditions.

Bio-solubilization of Chinese lignite I:extra-cellular protein analysis

A white rot fungus strain, Trichoderma sp.AH, was isolated from rotten wood in Fushun and used to study the mechanism of lignite bio-solubilization.The results showed that nitric acid pretreated Fushun lignite was solubilized by T.sp.AH and that extracellular proteins from T.sp.AH were correlated with the lignite bio-solubilization results.In the presence of Fushun lignite the extracellular protein concentration from T.sp.AH was 4.5 g/L while the concentration was 3 g/L in the absence of Fushun lignite.Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE) of the extracellular proteins detected at least four new protein bands after the T.sp.AH had solubilized the lignite.Enzyme color reactions showed that extracellular proteins from T.sp.AH mainly consisted of phenol-oxidases, but that lignin decomposition enzymes such as laccase, peroxidase and manganese peroxidases were not present.

Low temperature stress on the hematological parameters and HSP gene expression in the turbot Scophthalmus maximus

To study the effect of low temperature stress on hematological parameters and HSP gene expression in the turbot （Seophthalmus maximus）, water temperature was lowered rapidly from 18 to 1℃. During the cooling process, three individuals were removed from culture tanks at 18, 13, 8, 5, 3, and 1℃. Blood samples and tissues were taken from each individual, hematological indices and HSP gene expression in tissues were measured. The red blood cell count, white blood cell count, and hemoglobin concentration decreased significantly （P〈0.05） as temperature decreased. Enzyme activities of plasma alanine transaminase and creatine kinase increased as temperature decreased, whereas aspartic transaminase and γ-glutamyl transpeptidase activities displayed no obvious changes above 1℃ and lactate dehydrogenase activity increased first and then decreased. Blood urea nitrogen and uric acid levels were highest at 8℃, and creatinine concentration was highest at 3℃. The concentrations of plasma cortisol, cholesterol, and triglyceride all increased significantly （P〈0.05） as temperature decreased. The serum glucose concentration increased first and then decreased to the initial level. The HSP70 mRNA expression showed various patterns in different tissues, whereas HSP90 mRNA expression showed the same tendency in all tissues. Overall, these results indicate that temperature decreases in the range of 8 to 5℃ may induce a stress response in S. maximus and that temperature should be kept above 8℃ in the aquaculture setting to avoid damage to the fish.

Process Control and Optimization for Heterologous Protein Production by Methylotrophic Pichia pastoris

The methylotrophic yeast Pichia pastoris is a highly successful system for production of a variety of heterologous proteins due to its unique features/abilities for effective protein expression, and tremendous efforts have been made to increase heterologous protein productivity by P. pastoris in recent years. When new engineered yeast strains are constructed and are ready to use tot industrial protein production, process control and optimization techniques should be applied to improve the fermentation performance in the following aspects： （1） increase recombinant cell concentrations in fermentor to high density during growth phase; （2） effectively induce heterologous proteins by enhancing/stabilizing titers or concentrations of the proteins during induction phase; （3） decrease operation costs by relieving the working loads of heat-exchange and oxygen supply. This article reviews and discusses the key and commonly used techniques in heterologous protein production by P. pastoris, with the focus on optimizations of fermentation media and basic operation conditions, development of optimal glycerol feeding strategies for achieving high density cultivation of P. pastoris and effective heterologous protein induction methods by regulating specific growth rate, methanol concentration, temperatures, mixture ratio of multi-carbon substrates, etc. Metabolic analysis for recombinant protein production by P. pastoris is also introduced to interpret the mechanism of sub-optimal heterologous protein production and to explore further optimal expression methods.

SERUM CONCENTRATIONS OF HYALURONIC ACID, PROCOLLAGEN TYPE III NH_2-TERMINAL PEPTIDE, AND LAMININ IN PATIENTS WITH CHRONIC CONGESTIVE HEART FAILURE

Objective To explore the role of serum fibrotic indices including hyaluronic acid （HA）, procollagen type Ⅲ NH2-terminal peptide （PCIIIP）, and laminin （LN） in assessing the severity of myocardial fibrosis in chronic congestive heart failure （CHF）. Methods Serum levels of HA, PCIIIP, and LN in 39 patients with CHF E [14 with New York Heart Association （NYHA） functional class II, 21 with class Ⅲ, 4 with class Ⅳ] and in 46 patients with NYHA functional class I were assessed by radioimmunoassay. Results The serum concentrations of HA, PCMP, and LN were 359.75 ± 84.59 μg/L, 77.88 ± 24. 67 μg/L, 86. 73 ± 23.90 μg/L in CHF group, and 211.60 ±54. 80 μg/L, 64.82 ±23.99 μg/L, 82. 26 ±23.98 μg/L in NYHA functional class Ⅰ group, respectively. The HA level was significantly higher in CHF patients as compared with NYHA functional class Ⅰ group （ P 〈 0.05 ）. However, no difference was found in the levels of PCIIIP and LN between CHF group and NYHA functional class Ⅰ group. The serum HA concentration was negatively correlated with left ventricular ejection fraction （ r = - 0.71, P 〈 0.05 ）. Conclusion Serum HA level may act as an indicator for myocardial fibrosis.

Comparison of Three Methods of Protein Extraction from Dermatophagoides Pteronyssinus for Two-dimensional Electrophoresis

Obiective To explore an effective method of Dermatophagoides pteronyssinus protein extraction suitable for two-dimensional electrophoresis （2-DE） analysis. Methods The extracts of Dermatophagoides pteronyssinus were prepared with Coca＇s solution, lysis buffer of 2-DE, and Trizol reagent, respectively. Bicinchoninic acid （BCA） assay was used to determine the total protein concentration of the samples. The efficiency of different protein extraction methods were evaluated with 2-DE analysis. Results The concentrations of extracted protein by methods of Coca＇s solution, lysis buffer, and Trizol reagent were 0.63 g/L, 0.90 g/L, and 0.80 g/L, respectively. The 2-DE analysis results showed that some protein spots in low molecular weight （LMW） range could be detected with the Coca＇s solution method. With the lysis buffer of 2-DE method, more protein spots in LMW range could be detected, while the medium molecular weight （MMW） protein spots were absent. Several MMW protein spots （174-178 kD and 133 kD） and more LMW protein spots were detected withTrizol reagent method. Conclusions Among Coca＇s solution, lysis buffer of 2-DE, and Trizol reagent, the concentration of extracted protein of Dermatophagoides pteronyssinus by lysis buffer of 2-DE is the highest. However, most protein components of Dermatophagoides pteronyssinus purified mite bodies can be extracted by Trizol reagent, which may generally reflect the whole profile of Dermatophagoides pteronyssinus allergens.

Several factors including ITPA polymorphism influence ribavirin-induced anemia in chronic hepatitis C

AIM： To construct formulae for predicting the likelihood of ribavirin-induced anemia in pegylated interferon plus ribavirin for chronic hepatitis C. METHODS： Five hundred and sixty-one Japanese patients with hepatitis C virus genotype lb who had received combination treatment were enrolled and as- signed randomly to the derivation and confirmatory groups. Single nucleotide polymorphisms at or nearby ITPA were genotyped by real-time detection poly- merase chain reaction. Factors influencing significant anemia （hemoglobin concentration 〈 10.0 g/dL at week 4 of treatment） and significant hemoglobin decline （declining concentrations 〉 3.0 g/dL at week 4） were analyzed using multiple regression analyses. Prediction formulae were constructed by significantly independent factors. RESULTS： Multivariate analysis for the derivation group identified four independent factors associated with significant hemoglobin decline： hemoglobin decline at week 2 [P = 3.29× 10^4, odds ratio （OR） = 7.54 （g/dL）], estimated glomerular filtration rate [P = 2.16× 10^4, OR = 0.962 （ml/min/1.73 m2）], rs1127354 （P = 5.75 × 10^4, OR = 10.94） and baseline hemoglobin [P = 7.86 × 10^4, OR = 1.50 （g/alL）]. Using the model constructed by these factors, positive and negative predictive values and predictive accuracy were 79.8%, 88.8% and 86.2%, respectively. For the confirmatory group, they were 83.3%, 91.0% and 88.3%. These factors were closely correlated with significant anemia. However, the model could not be constructed, because no patients with rs1127354 minor genotype CA/AA had significant anemia. CONCLUSION： Reliable formulae for predicting the likelihood of ribavirin-induced anemia were constructed. Such modeling may be useful in developing individual tailoring and optimization of ribavirin dosage.

Characterization of Bovine and Ovine WPC Obtained by Different Membrane Configuration Processes

The objective of this stud）, was to valorize bovine and ovine cheese whey resulting from small and medium cheese manufacture plants, by producing liquid and dr）＂ whey protein concentrates （LWPC and WPC）. The flexibility implemented by batch ultrafiltration （UF） and diafiltration （DF） allowed for the production and ovine WPC with 61 -87% （dry basis）. Diatiltration, performed in of liquid bovine WPC with 43-66% protein contents （dry basis） sequential dilution mode （DFsdm） did not improve significantly the composition of WPC liquid products comparing to the results achieved by conventional UF. However, using DF in volume reduction mode （DFvrm） protein content was increased more than 20% comparing to conventional UF. Ovine products showed higher protein levels （62-84% dry basis） what makes their manufacture attractive. Protein profiles varied with the whey origin and with the concentration process. Using batch DFvrm was possible to obtain richer protein products free of low MW compounds.

Oxidative stress responses of submerged macrophyte Vallisneria asiatica to different concentrations of cyanobacteria

In a 10-day aquarium experiment, this investigation examines macrophyte restoration in eutrophic Lake Taihu, the physiological effects of different plant biomass levels and of increasing natural cyanobacterial concentrations on a submerged macrophyte, Vallisneria asiatica. Cyanobacterial stress suppressed the superoxide dismutase （SOD） activity of the plant＇s leaves and induced the catalase （CAT） and peroxidase （POD） activities of its roots. The soluble protein content in V. asiatica decreased with an increase in natural cyanobacterial concentrations, whereas the malonaldehyde （MDA） increased significantly at chlorophyll a （Chl a） concentrations of 222 and 262 μg/L in water. V. asiatica adapted to the stress caused by cyanobacterial concentrations by adjusting its antioxidant defense system to remove the excessive reactive oxygen species when the algal Chl a concentration was 〉109 μg/L. Additionally, high biomass of V. asiatica （2 222 g FW/m^2） can inhibit the reproduction of cyanobacteria more significantly than low biomass （1 111 g FW/m^2）. High biomass of V. asiatica increased the oxidative stress in an individual plant when the initial Chl a concentration in the water reached 222 and 262 μg/L, as expressed by the increased MDA in leaves, compared with low biomass of K asiatica. This provides a basis for controlling cyanobacterial concentrations and V. asiatica biomass for the recovery of V. asiatica in eutrophic Lake Taihu.

Relationship between C-reactive protein and clinical stage in nasopharyngeal carcinoma

Objective： The aim of our study was to explore the correlations between C-reactive protein （CRP） levels and clinical stages of nasopharyngeal carcinoma （NPC）. Methods： We analyzed 108 cases, among them, 68 cases were NPC, 20 cases were benign inflammatory diseases of nasopharynx, 20 cases were healthy volunteers as control. CRP was determined with immunoturbidimetry （ITM）. Results： The mean concentrations of CRP in NPC （19.76 rag/L） were significantly increased compared to that in the control group （6.23 mg/L）, while were significantly lower than that in benign inflammatory group （45.63 mg/L）; The mean concentrations of CRP in T4 group （25.58 mg/L） were higher than that in T1 group （17.35 mg/L）, T2 group （18.65 mg/L） and T3 group （15.61 mg/L）. The mean concentrations of CRP in N3 group （28.04 mg/L） were higher than that in NO （17.62mg/L）, N1 （21.27 mg/L）, N2 （18.62 mg/L） respectively, the mean concentrations of CRP in IV （25.74 mg/L） were higher than that in I （14.20 mg/L）, II （16.10 mg/L）, III （23.01 mg/L）, respectively. Conclusion： The serum CRP level is associated with the occurrence of NPC and benign inflammatory disease of nasopharynx. In NPC, the CRP level has positive relationship with the TNM stage.

Utilization of Yellowfin Tuna and Red Snapper Roe Protein Concentrate as Emulsifier in Mayonnaise

Roes of yellowfin tuna （Thunnus albacares） and red snapper （Lutjanus champecanus） are considered as abundant and underutilized by-product in Indonesia. The production of roe protein concentrate （RPC） is expected to increase the economic value and potency of their usage. Tuna and red snapper RPC was defatted using etano195% with one, two, three and four times of repetition. Both RPC made with four times repetition of defatting had the highest protein content （79.90% and 80.72%）, showed high emulsion activity （97.46% and 99.62%） and emulsion stability （97.10% and 99.48%）, and decreased the interfacial tension of 51% and 55.9%, respectively. Mayonnaise was made with 0, 25, 50, 75 and 100% substitution level of each RPC with four times repetition ofdefatting. The physical, chemical and organoleptic properties of mayonnaise were studied. The best mayonnaise formulation was obtained from 50% substitution level of tuna and red snapper RPC. Mayonnaise with tuna and red snapper RPC had good viscosity （5,920 cPs and 5,845 cPs）, high emulsion stability （90.5% and 91.73%） and small fat globule size （±2.5 lam and ± 2.25 lam）, respectively. These mayonnaises also showed high score of spreadability and low intense of fishy odor. However they still had quite strong of fishy flavor based on scoring test.

Preparation and Charaterization of Self-assembled Nanoparticles Based on Linolenic-acid Modified Chitosan

Chitosan was modified by conjugating coupling with linolenic acid through the 1-ethyl-3-（3-dimethylami- nopropyyl） carbodiimide （EDC）-mediated reaction. The degree of substitution 1.8% （ i.e. 1.8 linolenic acid group per 100 anhydroglucose units） was measured by ^1H NMR. The critical aggregation concentration （CAC） of the self-aggregate of hydrophobically modified chitosan was determined by measuring the fluorescence intensity of the pyrene as a fluorescent probe. The CAC value in phosphate-buffered saline （PBS） solution （pH 7.4） was 5 × 10^-2 mg mL^-1. The average particle size of selfaggregates of hydrophobically modified chitosan in PBS solution （pH7.4） was 210.8 nm with a unimodal size distribution ranging from 100 to 500 nm. Transmission electron microscopy （TEM） study showed that the formation of near spherical shape nanoparticles has enough structural integrity. The loading ability of hydrophibically modified chitosan （LA-chitosan） was investigated by using bovine serum albumin （BSA） as the model. The loading capacity of self-aggregated nanoparticles increases （ 19.85 % ± 0.04 % to 37.57 % ± 0.25 % ） with the concentration of BSA （0.1-0.5 mg mL^-1 ）.

Development of Value Added Dahi by Incorporating Cereal and Fruits

A study was conducted for the development of value added dahi by incorporating fruit pulps, cereal flour and whey proteins concentrate （WHC） to increase the nutritional and sensory quality. Value added dahi （VAD） was prepared by using skim milk, oat flour and WPC. VAD with 1% oat flour, 1% whey protein concentrate was found to be highly acceptable by sensory evaluation and curd tension study. Statistically there was a highly significant difference （P 〈 0.05） between skim milk dahi （control） and VAD VAD scored highest sensory score for all the sensory parameters studied. Curd tension found to be markedly increased in value added dahi with increased firmness of the product. Value added stirred dahi was prepared with oat flour, whey protein concentrate, papaya, fig pulps and sugar with different combination in order to assess the suitable level of addition with maximum acceptability. Value added stirred dahi （VADl） with 1% oat flour, 1% WPC, 5% papaya pulp, 4% sugar combination was found to be acceptable among the other combinations. Storage studies evaluated by sensory score revealed that the value added dahi can be stored up to 7 days at 5 ^（2. A significant increase in acidity and decrease in pH were noticed in the VAD1 during the storage period but within the permissible limit. Statistical analysis revealed no significance difference （P 〉 0.05） in total count and yeast and mould count between VAD0 （control） and VADl during storage 5 ~C. Total yield of value added dahi increased along with cost of production due to increased cost of ingredients （fruits and whey protein concentrate） used for value addition.

Real and Legal Nutritional Alternative （e.g. Application of Free Amino Acids） to Replace Forbidden Doping Substances to Produce Excellent Sport Performance

Peformance enhancing drugs are widely used today in different sport fields, and therefore the successful anti-doping activity should be based not only on regular doping controls, but also it should show the real alternative： how to replace the forbidden doping substances with legal and effective supplements. The paper deals with application proposition of protein concentrates, free AA （amino acids）, HMB （hydroxy-methyle-butyrate）, creatine and camitine. If the athlete is involved in strength and power sport （e.g. throwing events in track and field, olympic weightlifting etc.）, the explosive and maximum strength is of primary importance. For strength athletes, these mentioned substances are those legal preparates, supplements, which can help effectively in performance improvement of sport results. The main reason is that using protein concentrates, AAs, HMB, creatine and camitine, the anabolic （and anticatabolic） effect will enhance the protein biosynthesis of the organism, improve the aerob and anaerob capacity of the athletes, activate and stimulate the own hormonal system. And the final result is creating higher loadability because of the faster recovery, and higher performance level on the competition. Of course, the athletes--as a minimum requirement--need an adequate nutrition （good balanced nourishment）, as well, with appropriate application and supplementation of all vitamins and essential minerals.